Epidemiologic studies have identified an association between iron and colorectal cancer. To date, no studies have examined the association between iron and a precursor lesion of colorectal cancer, adenomatous colonic polyps. In that the large majority of cancers arise from adenomatous polyps, it would be of great importance to determine if an iron-polyps relationship exists. The primary objective of this project is to test the hypothesis that there is an association between elevated body iron stores and adenomatous polyps of the colon. We will examine this hypothesis in a case-control study of six hundred men with and without polyps and in a substudy among a screening population of 120 cases and controls with and without polyps. Body iron stores, as determined by serum ferritin and transferrin levels, will be correlated with presence or absence of disease. The secondary objective of this project is to examine, within the framework of the case-control study, the genetic and environmental influences on body iron stores. To examine the genetic factors, we will use DNA polymorphisms to correlate genetic variants at iron related loci with serum measures of iron stores. To examine environmental factors, we will collect dietary information from all participants in the study and correlate the dietary data with that of the serum and genetic measures. The identification of iron as a risk factor for adenomatous polyps would be of great significance given the high incidence of polyps in older age groups and the ability to easily decrease iron stores, and thereby, possibly decrease the risk of colorectal carcinoma.